I guess John Carmack falls somewhere in between but as a complete layperson when he said he gave AGI by 2030 a 50 percent chance, that at least indicated to me that some really smart people think there is a chance.
2. He raised $20MM for an AI startup, which is fine and well but also makes him not entirely disincentivized from hype.
3. I wouldn't characterize him as someone in the trenches of deep learning.
More of a meta point: technical depth in more than a few things is impossible in a human lifespan, and just a bit harder once you become a "somebody" since a portion of your life becomes consumed by the fact that you're a "somebody". You end up doing things like raising VC money and starting companies with bold ambitions. Its own time sink.
I had this realization when I had a conversation with Lamport about a niche topic in distributed systems and he expressed a position that was just wrong. It was a minor point that didn't really matter much at all, but he was pretty confident in a conjecture I knew was wrong. To be clear, the fact that no one can be an expert on everything -- even everything within a subfield of CS -- doesn't detract from the fact that geniuses exist. Someone can "forget more than you know" and also not know something that you know. Life is just sadly very short.